Activation is Microsoft’s way of verifying that Windows is installed on a number of devices allowed by the license. An copy:
To download a legitimate Windows 8.1 Pro 64 Bit Activated ISO, follow these steps: Download Windows 8.1 Pro 64 Bit Activated Iso
: Retail and "Consumer" ISOs are no longer hosted on the main Microsoft software download hub. Activation is Microsoft’s way of verifying that Windows